Development from a single cell to a multicellular organism requires a dynamic interaction of signal transduction networks. The continuous exchange of information between cells through both contact and diffusible molecules influences gene expression and cell behavior. Our research focuses on cell-cell signaling events that lead to intracellular calcium release. We integrate in vivo image analysis coupled with molecular-genetic tools to elucidate the role of calcium-dependent signaling networks critical in developmental processes such as body plan formation and organogenesis in the zebrafish. The zebrafish (danio rerio) model system for vertebrate developmental biology has many attributes including genetics, rapid development and translucent embryos. Due to the remarkable conservation of developmental processes and mechanisms among vertebrates, we also use zebrafish as a model for human disease and test candidate genes.